The compound R-(+)-.alpha.-(2,3-Dimethoxyphenyl)-1-[2-(4-fluorophenyl)ethyl]-4-piperidi nemethanol (hereafter referred to as the "COMPOUND") is a 5HT2a antagonist useful in the treatment of a variety of disorders. U.S. Pat. No. 5,169,096 claimed compounds having a generic scope which encompassed the COMPOUND and disclosed uses of the treatment of anorexia nervosa, variant angina, Raynaud's phenomenon, coronary vasospasms, prophylactic treatment of migraine, cardiovascular diseases such as hypertension, peripheral vascular disease, thrombotic episodes, cardiopulmonary emergencies and arrythmias, and has anesthetic properties. See also U.S. Pat. Nos. 4,783,471; 4,912,117; and 5,021,428, which are divisions of U.S. Pat. No. 5,169,096. See also U.S. Pat. No. 4,877,798 (fibromyalgia), U.S. Pat. No. 4,908,369 (insomnia); U.S. Pat. No. 5,106,855 (glaucoma); EP 319 962 (anxiety); EP 337 136 (extrapyramidal symptoms). All of the foregoing are incorporated herein by reference.
The COMPOUND was then specifically claimed in U.S. Pat. No. 5,134,149 which disclosed uses of antagonizing serotonin at the 5Ht2 receptor, treating anxiety, variant angina, anorexia nervosa, Raynaud's phenomenon, intermittent claudication, coronary or peripheral vasospasms, fibromyalgia, extrapyramidal symptoms, arrythmias, thrombotic illness, transient ischemic attacks, drug abuse, and psychotic illness such as schizophrenia and mania. See also U.S. Pat. Nos. 5,561,144; 5,700,812; 5,700,813; 5,721,249--divisionals of U.S. Pat. No. 5,134,149--and also U.S. Pat. No. 5,618,824 (obsessive compulsive disorder) and PCT/US97/02597 (depressive disorders including major depressive episode and dysthymia, and bipolar disorder).
The COMPOUND is highly selective in its activity at the 5HT2receptor compared to other receptors, and, as such, has reportedly fewer side effects. It has been shown to have a better CNS safety index relative to the reference compounds haloperiodol, clozapine, risperiodone, ritanserin, and amperozide in preclinical testing. JPET 277:968-981, 1996, incorporated herein by reference. It has recently been discovered that this COMPOUND is useful in the treatment of Sleep Disorders such as insomnia and obstructive sleep apnea.
Chronic insomnia among adults in the United States has been estimated to be present in ten per cent of the adult population, and the annual cost for its treatment is estimated at $10.9 billion. JAMA 1997; 278: 2170-2177 at 2170. Chronic insomniacs report elevated levels of stress, anxiety, depression and medical illnesses. The most common class of medications for treating insomnia are the benzodiazepines, but the adverse effect profile of benzodiazepines include daytime sedation, diminished motor coordination, and cognitive impairments. Furthermore, the National Institutes of Health Consensus conference on Sleeping Pills and Insomnia in 1984 have developed guidelines discouraging the use of such sedative-hypnotics beyond 4-6 weeks because of concerns raised over drug misuse, dependency, withdrawal and rebound insomnia. JAMA 1997; 278: 2170-2177 at 2170. Therefore, it is desirable to have a pharmacological agent for the treatment of insomnia which is more effective and/or has fewer side effects that those currently used.
The prevalence of obstructive sleep apnea is estimated to be approximately 1-10% in the adult population, but may be higher in elderly individuals. DIAGNOSTIC AND STATISTICAL MANUAL OF MENTAL DISORDERS 4.sup.th ed., American Psychiatric Association, Washington D.C. Preliminary evidence suggests that having obstructive sleep apnea may contribute to increased susceptibility to cardiovascular complications such as hypertension, cardiac arrhythmias, stroke, and myocardial infarction. Excessive daytime sleepiness is also a major complication.
Currently, the therapies used to treat obstructive sleep apnea include weight loss for the obese patient, Nasal-continuous positive Airway Pressure (a facemask used at night which produces a positive pressure within the upper airway), pharyngeal surgery and the administration of a variety of pharmacologic agents which have not been proven to be entirely successful. Chest 109 (5):1346-1358 (May 1996) entitled Treatment of Obstructive Sleep Apnea, a Review, hereby incorporated by reference. These agents include Acetazolamide, Medroxyprogesterone, Opioid Antagonists, Nicotine, Angiotensin-Convertying Enzyme Inhibitors and Psychotropic Agents (including those that prevent the reuptake of biogenic amines such as norepinephreine, dopamine and serotonin). Id. At 1353. Many of these pharmacological agents used also have a ventilatory depressant action (such as benzodiazepines) or other side effects such as urinary hesitancy and/or impotence in men (Protriptyline) so that a new agent with fewer side effects is needed for the treatment of obstructive sleep apnea. Even though serotonin is a sleep-inducing agent and may be a ventilatory stimulant (Id. At 1354), the COMPOUND of the present invention, which inhibits serotonin at the 5HT2a receptor, has been found useful in treating obstructive sleep apnea. See also Am. J. Respir Crit Care Med (153) pp 776-786 (1996) where serotonin antagonists exacerbated sleep apnea produced in English bulldogs. But compare, Journal of Physiology (466) pp 367-382 (1993), where it is postulated that an excess of serotonin due to dysfunction of the serotonin biosynthesis mechanisms might set up conditions which favor obstructive apneas; European Journal of Pharmacology (259):71-74 (1994)further work on rat model with 5ht2 antagonist.
Insomnia and Obstructive Sleep Apnea are sometimes found in conjunction with other conditions and sometimes those conditions are treatable by the COMPOUND, e.g., patients suffering from fibromyalgia may also have insomnia and/or sleep apnea. Am J Med Sci 1998; 315(6):367-376. Having one pharmacological agent which treats two or more existing or potential conditions, as does the present invention, is probably more cost effective, leads to better compliance and has fewer side effects than taking two or more agents.
It is an object of the present invention to provide a therapeutic agent for the use in treating Sleep Disorders. It is another object of the present invention to provide one pharmaceutical agent which may be useful in treating two or more conditions wherein one of the conditions is insomnia or sleep apenea and other Conditions respond to treatment by the COMPOUND.